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Discussion Starter · #1 ·
My '66 C4 automatic has a fluid line on the driver side that runs horizontally forward then turns 90 degrees down and ends just above the neutral safety switch. The end is open and leaks trans oil profusely when my car sits. Is this line supposed to be an overflow tube? Is it supposed to have some kind of hose or connector on it? If it is supposed to be open, why is my tran. dumping so much oil out of it when my car sits? Thanks..........
 

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That's your case vent tube.....

Usually isn't a problem unless the rotating parts are foaming the trans fluid and throwing it all over the place....how does your trans fluid level look when checked? Overfilling is a common cause of vent tube leakage. Another cause is a leaky converter check, which allows oil from the converter to drain back into the case, raising the level and causing spillage out the vent tube.

I have a similar problem on the race car due to starting line G forces...fluid stacks rearward, gets picked up by trans parts spinning at high rpm and some of the mess goes out the tube. I solved the problem by running a hose to my oil puke tank....since the tank is roughly 13" or so above the vent tube, any ATF thrown out usually rises in the hose and then drops back. Haven't seen any show up in the puke tank.
 

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I am having a similar problem, I replaced the C4 selector shaft and bracket seals (ATP control shaft seals FO-15), which required me to remove the fluid, plan, and gasket and then the valve body. When removing the valve body I did not see any springs, balls, or pins when I removed it and the install of the two new seals went fairly easy. When putting the valve body back I only had a little trouble getting the linkage and spring plunger to engaged the kickdown properly but after a few attempts got it. I replaced the filer, ensured the pan flange was flat and level and before resecuring it to the transmission with a new pan gasket. I filled the transmission with some fluid, checked for leaks and found now, phew, and the started her up and let her warm up to normal operating temperature and then rechecked. Of course it needed fluid but when I added fluid it started coming out of the overflow tube on the drivers side of the transmission just above the selector shaft and bracket. I am not sure what to investigate next? Anybody have any ideas? What could I have screwed up. I did not take the valve body apart, i.e. split the two metals halves that make up the valve body. Any help would be greatly appreciated.
 

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There's a very good chance that your fluid was slightly aerated from air still within the system. Did your fluid show signs of having bubbles? Was your engine running when you were adding fluid? After dropping the pan, you have to refill the system with the engine running (and the car fairly level, at least 4 wheels on the ground).
 
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